Advertisements
Advertisements
प्रश्न
What is thermionic emission?
Advertisements
उत्तर
The emission of electrons from a metal surface when heat energy is imparted to it is called thermionic emission
APPEARS IN
संबंधित प्रश्न
When is said to be the nucleus unstable?
Give the relative ionizing power of α, β and γ radiations.
In the following fig. shows a radioactive source S in a thick lead container. The radiations pass through an electric field between the plates P and Q. Complete the diagram to show the paths of α , β and γ radiations.
Why is the source S placed in a thick lead container?
What do you understand by the term radioactivity?
A certain nucleus has a mass number 20 and atomic number 9. Find the number of neutrons and protons present in it.
From α, β and γ-rays, name the one which travels with the speed of light?
Which of the following statements is/are correct?
- α particles are photons
- Penetrating power of γ radiation is very low
- Ionization power is maximum for α rays
- Penetrating power of γ radiation is very high
In U238 ore containing Uranium the ratio of U234 to Pb206 nuclei is 3. Assuming that all the lead present in the ore is final stable product of U238. Half life of U238 to be 4.5 × 109 years and the age of ore is ______ × 109 years. (in 109 years)
